This invention relates to apparatus for counting bills, bank notes, security papers, cards, or like sheets of paper (hereinafter generally referred to as "sheets").
Sheet counting apparatus of the type now under consideration usually comprises a sheet stand for holding a neat pack of sheets to be counted, and an infeed mechanism for feeding, either frictionally or by suction, successive sheets to the next stage in the apparatus. The sheets thus supplied into the apparatus are counted before they are transported to a prescribed recovery position. The suction-type infeed mechanism, usually employing a movable suction head mounted opposite to the sheet stand, is disadvantageous in that it makes the overall apparatus inconveniently bulky and complex in construction because there must be incorporated therein a vacuum pump or the like communicating with the suction head and a mechanism for causing the desired intricate movement of the suction head.
The friction-type infeed mechanism, utilizing one or more rolls rotatably mounted for frictional circumferential contact with the foremost one of the sheets in the sheet stand, can make the sheet counting apparatus far simpler and less expensive in construction. However, this type of apparatus tends also to become bulky in size because the counting and some other constituent mechanisms of the apparatus are arranged along the path of travel of the successive sheets from the sheet stand to the recovery mechanism. In order to minimize the size of the apparatus, the counting and like mechanisms should be positioned as close as possible to the sheet stand.
Another problem accompanying the prior art sheet counting apparatus concerns its counting mechanism which heretofore has utilized either a phototube or microswitch. The service life of the phototube-type counting mechanism is significantly reduced if the spacings between the successive sheets traveling past the phototube are irregular, because such irregularity adversely affects the electrical circuitry of the mechanism. Furthermore, the inevitable dust accumulation on the phototube impairs its proper functioning. The microswitch as used in the conventional counting mechanism has ordinarily been positioned midway along the path of travel of the successive sheets from the sheet stand to the recovery mechanism, so as to respond to the thickness of each sheet traveling therepast. The microswitch thus arranged is required to be highly sensitive and tends to operate erroneously in the event the sheets are supplied irregularly from the sheet stand.
A further difficulty accompanying the piror art apparatus makes its appearance when the same is employed for counting bills of various denominations, which ordinarily differ in size. The various parts of the prior art apparatus have mostly been designed to accommodate sheets of predetermined dimensions only. For counting bills or other sheets of various sizes by a single apparatus, therefore, several interchangeable sheet stands, sheet recovery receptacles and the like have had to be prepared for the respective sizes of sheets.